Binding of the 7SK snRNA turns the HEXIM1 protein into a P-TEFb (CDK9/cyclin T) inhibitor.
Détails
ID Serval
serval:BIB_C61A22494742
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Binding of the 7SK snRNA turns the HEXIM1 protein into a P-TEFb (CDK9/cyclin T) inhibitor.
Périodique
Embo Journal
ISSN
0261-4189 (Print)
ISSN-L
0261-4189
Statut éditorial
Publié
Date de publication
2004
Peer-reviewed
Oui
Volume
23
Numéro
13
Pages
2608-2619
Langue
anglais
Notes
Publication types: Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, P.H.S.
Publication Status: ppublish
Publication Status: ppublish
Résumé
The positive transcription elongation factor b (P-TEFb) plays a pivotal role in productive elongation of nascent RNA molecules by RNA polymerase II. Core active P-TEFb is composed of CDK9 and cyclin T. In addition, mammalian cell extracts contain an inactive P-TEFb complex composed of four components, CDK9, cyclin T, the 7SK snRNA and the MAQ1/HEXIM1 protein. We now report an in vitro reconstitution of 7SK-dependent HEXIM1 association to purified P-TEFb and subsequent CDK9 inhibition. Yeast three-hybrid tests and gel-shift assays indicated that HEXIM1 binds 7SK snRNA directly and a 7SK snRNA-recognition motif was identified in the central part of HEXIM1 (amino acids (aa) 152-155). Data from yeast two-hybrid and pull-down assay on GST fusion proteins converge to a direct binding of P-TEFb to the HEXIM1 C-terminal domain (aa 181-359). Consistently, point mutations in an evolutionarily conserved motif (aa 202-205) were found to suppress P-TEFb binding and inhibition without affecting 7SK recognition. We propose that the RNA-binding domain of HEXIM1 mediates its association with 7SK and that P-TEFb then enters the complex through association with HEXIM1.
Mots-clé
Amino Acid Motifs, Amino Acid Sequence, Cyclin T, Cyclin-Dependent Kinase 9/metabolism, Cyclins/metabolism, Electrophoretic Mobility Shift Assay, Escherichia coli/genetics, Glutathione Transferase/metabolism, HeLa Cells, Humans, Models, Biological, Molecular Sequence Data, Mutation, Positive Transcriptional Elongation Factor B/antagonists & inhibitors, Positive Transcriptional Elongation Factor B/genetics, Precipitin Tests, Protein Structure, Tertiary, RNA, Small Nuclear/metabolism, RNA-Binding Proteins/chemistry, RNA-Binding Proteins/genetics, Recombinant Fusion Proteins/chemistry, Recombinant Fusion Proteins/isolation & purification, Two-Hybrid System Techniques
Pubmed
Web of science
Création de la notice
28/07/2008 17:00
Dernière modification de la notice
20/08/2019 16:41